Systems and methods for cooling of superconducting power transmission lines

ABSTRACT

A cooling system includes a coolant transmitter that transmits coolant at a pressure greater than atmospheric pressure. The cooling system also includes an evaporation vessel at atmospheric pressure. The evaporation vessel can contain an amount of coolant at the boiling point of the coolant. The cooling system also includes a pressure reducer fluidically coupled to the coolant transmitter and the evaporation vessel. The pressure reducer can include an orifice. The cooling system is configured such that heat is transferred from the coolant in the coolant transmitter to the coolant contained in the evaporation vessel. An exit stream conduit can fluidically couple the coolant transmitter and the pressure reducer, with the exit stream conduit diverting a portion of the coolant from the coolant transmitter to the evaporation vessel.

RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 63/115,226, filed Nov. 18, 2020 and titled“Systems and Methods for Cooling of Superconducting Power TransmissionLines,” the disclosure of which is hereby incorporated by referenceherein in its entirety.

FIELD

The present disclosure is related to the field of electricitytransmission, and more specifically, to the cooling of powertransmission lines.

BACKGROUND

Electric power is typically moved from its point of generation toconsumer loads using an electric power grid (“the grid”). Electric powergrids include components such as power generators, transformers,switchgear, transmission and distribution lines, and control andprotection devices.

SUMMARY

Embodiments described herein relate to cooling systems and coolingmethods, and can be implemented in the cooling of power transmissionlines and power transmission systems. In one aspect, a cooling systemdescribed herein can include a coolant transmitter that transmitscoolant at a pressure greater than atmospheric pressure. The coolingsystem further includes an evaporation vessel at atmospheric pressureconfigured to contain an amount of coolant at the boiling point of thecoolant. The cooling system further includes a pressure reducerfluidically coupled to the coolant transmitter and the evaporationvessel. The cooling system is configured such that heat is transferredfrom the coolant in the coolant transmitter to the coolant contained inthe evaporation vessel. In some embodiments, an exit stream conduit canfluidically couple the coolant transmitter and the pressure reducer,with the exit stream conduit diverting a portion of the coolant from thecoolant transmitter to the evaporation vessel. In some embodiments, thepressure reducer can include an orifice. In some embodiments, thepressure reducer can include a valve. In some embodiments, the pressurereducer can include a throttle. In some embodiments, a level sensor canbe disposed in the evaporation vessel. In some embodiments, the coolantcan include liquid nitrogen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example cooling system, according to anembodiment.

FIG. 2 illustrates a cooling system including a throttle, a levelsensor, and a heat exchanger, according to an embodiment.

FIG. 3 illustrates a cooling system including a level sensor, athermally insulating jacket, and a heat exchanger, according to anembodiment.

FIG. 4 illustrates a cooling system including an orifice, a thermallyinsulating jacket, and a heat exchanger, according to an embodiment.

FIGS. 5A-5B illustrate a cooling system with a spray mechanism,according to an embodiment.

FIG. 6 illustrates a cooling system with a heat exchanger as anevaporation vessel, according to an embodiment.

FIG. 7 illustrates a cooling system with a counter current evaporationvessel, according to an embodiment.

FIG. 8 illustrates a cooling system with a counter current evaporationvessel and a header tube, according to an embodiment.

FIGS. 9A-9B illustrate a cooling system with evaporation tubes anddetails thereof, according to an embodiment.

FIG. 10 illustrates a cooling system with an orifice and a heatexchanger, according to an embodiment.

FIG. 11 is a diagram of a method of cooling a subcooled liquid,according to an embodiment.

DETAILED DESCRIPTION

Embodiments described herein relate to cooling systems and coolingmethods. In some embodiments, cooling systems and cooling methodsdescribed herein can be implemented in the cooling of power transmissionsystems with superconductor cables. Superconductor cables employed inpower transmission systems can operate at up to 10 times the current ofconventional wire while maintaining superconductivity. Higher currentallows for lower voltage and smaller rights-of-way. Additionally, energycan be transferred through power transmission systems at a higher ratethrough narrow rights-of-way with reduced energy losses, as contrastedwith known systems. Moreover, by incorporating active cooling mechanismsinto power transmission systems with superconductors, power transmissionlines of the present disclosure can exhibit reduced sag and creep and/ormore consistent sag and creep over time (e.g., in the case of overheadpower transmission), and generally more consistent performance (for bothoverhead and underground power transmission) as contrasted with knownsystems. For example, power transmission lines of the present disclosuremay exhibit sag and/or creep that are not variable, or that do notsubstantially vary, over time, in view of the actively controlledtemperature of the power transmission lines.

Known electric power transmission systems use continuous electricalconductors to interconnect power generation stations with consumerloads. Power generation stations, such as thermal (e.g., steam-driven),nuclear, hydroelectric, natural gas, solar and wind power plants,generate electric energy at AC voltages typically ranging between 15 kVand 25 kV. To transport the energy over long distances, the associatedvoltage is increased at the power generation station, for example via astep-up transformer. Extra-high-voltage (EHV) power transmission linescan transport the energy to geographically remote substations atvoltages of 230 kV and above. At intermediate substations, the voltagecan be reduced to high-voltage (HV) levels via a step-down transformer,and the energy is transported to HV substations via power transmissionlines that operate at voltages ranging from 220 to 110 kV. At HVsubstations closer to the loads, the voltage is further reduced to 69kV, and sub-transmission lines connect the HV substations to the manydistribution stations. At the distribution substations, the voltage isreduced to a value in the range of 35 kV to 12 kV before beingdistributed to the loads at 4160/480/240/120V via pole-top orpad-mounted step-down transformers. The precise voltages used intransmission and distribution vary slightly in different regions anddifferent countries.

In the United States, an EHV power transmission line has a nominalvoltage of between 230 kV and 800 kV, and a HV power transmission linehas a nominal voltage of between 115 kV and 230 kV. For voltages ofbetween 69 kV and 115 kV, the line is considered to be at asub-transmission level, and below 60 kV it is considered to be at adistribution level. The voltage values demarcating these designationsare somewhat arbitrary, and can vary depending on the authority havingjurisdiction and/or the location. Known EHV power transmission lines cantransport energy as far as 400-500 miles, whereas HV power transmissionlines can transport energy as far as 200 miles, and sub-transmissionlines can transport energy for 50-60 miles. High-voltage DC (HVDC) powertransmission lines are used to transmit energy over long distances orunderwater. In a HVDC system, AC voltage generated by a generator isrectified, and the energy is transmitted via a DC cable to the receivingstation, where an inverter is used to convert DC voltage back to AC.

Superconducting materials have zero or near-zero electrical resistivitywhen cooled below their critical temperature. Superconducting materialspresently available as wires or tapes have critical temperatures belowapproximately −150° C. (123 K). Some underground cables includesuperconducting materials cooled by flowing liquid nitrogen (LN) attemperatures below −196° C. (77 K) and enclosed in a thermallyinsulating jacket (“TIJ”). Superconducting cables have very low energylosses due to resistance if multiple superconducting wires are joined.Superconducting cables generate some energy losses in superconductorswhen carrying AC currents (“AC losses”), some energy losses due tochanging magnetic fields (“magnetic losses”) and have some heat leakthrough the TIJ. Superconducting cables carrying DC current have smallerlosses, dominated by the heat leak through the TIJ. Heat generated byenergy losses and leaking into the cooled region can be removed by acoolant to maintain the superconductor within its operating temperaturerange.

In known superconducting transmission deployments, coolant typicallyenters the cable as a sub-cooled liquid, for example at a temperature of68 K and at a pressure of 20 bar. The energy losses generate heat withinthe TIJ and the heat can be removed by the flowing of coolant. Thetemperature of the coolant therefore increases as it flows along thecable due to this heat energy. The temperature increase depends on theheat energy (W/m), the flow rate (kg/s) of the coolant, the length ofcable (m), and the specific heat capacity of the coolant (J/kg-K). Theflowing coolant has a maximum allowable temperature. This maximumallowable temperature has limited the length of superconducting cablesdeployed.

As used herein, “subcooled liquid” refers to a liquid that is at atemperature lower than its boiling point at a given pressure. Forexample, at atmospheric pressure (i.e., 760 mmHg), the boiling point ofnitrogen is about 77.4 K. Thus, nitrogen would be a subcooled liquid atatmospheric pressure and a temperature of 70 K. At 20 bar absolute, theboiling point of nitrogen is about 115 K. Thus, nitrogen is a subcooledliquid at a pressure of 20 bar absolute and a temperature of 77.4 K (itsboiling point at atmospheric pressure).

As an example, if 1 kg/s of LN can flow into a cable at 68 K. Thissubcooled LN is produced by cooling LN from storage (or from previoususe in the cable). If 5 W/m of heat is to be removed, the LN will warmby 1 K every 400 m. If an upper temperature limit of 75 K is permissible(e.g., given a heat capacity of 2 J/gK for LN, or 1 J/gK for liquidnatural gas), the cable section length is limited to 2.8 km. At thispoint, the LN must be re-cooled to 68 K. Note that once in the cable theLN does not boil. In some cases, cooling can utilize latent heat and nospecific heat. LN boils under atmospheric pressure at 77.4 K, so coolingto near 77.4 K is relatively straightforward using an evaporator open toatmospheric pressure. The equipment for cooling 1 kg/s of LN below 77.4K is significant. The equipment for re-cooling (placed every 2.8 km inthe example above) is similar in complexity to the equipment for initialcooling of LN before entry into the power line. This may be accomplishedby maintaining a reduced pressure of a boiling pool of LN using pumps,or by mechanical refrigeration.

Both of the above mentioned methods have significant drawbacks. First,there are many moving parts, and reliability is important for each ofthem in operation of a power grid. This can often entail multipleredundant circuits. Capital cost of the cooling equipment, the site(about 50 m² or more may be desirable), and access rights to the siteare also drawbacks. Additionally, operating cost can be substantial.Refrigeration systems consume a large amount of electrical power (on theorder of 100 kW and above). The power needed for cooling increases withthe power transmitted. Power transmission is typically at its highestwhen electrical power is in short supply and energy is most expensive.Complex systems also need periodic maintenance, which can add to theoperating costs.

Transmission lines are often used to transport electricity over longdistances. High voltage, high power transmission lines may be hundredsof km long and pass through remote areas. Placing a re-cooling stationevery few km is generally not practical or economic. There may be nosuitable power source, noting that transmitted power may not be readilyavailable to operate the cooling system. The voltage of the transmittedpower can be too high or DC. Access for maintenance can be difficult,and the overall system reliability may be low due to multiple units inseries, siting and land area may be a problem and capital expense can behigh.

The shortcomings of the cooling systems described above have beenovercome in demonstration systems, but have placed significantimpediments to the wider deployment of superconducting power cables inthe electricity grid. It is therefore desirable to have a cooling systemthat overcomes these problems.

According to some embodiments described herein, a coolant can enter anunderground or overhead cable of a transmission line at the approximateatmospheric boiling point of the coolant (i.e., the approximate boilingpoint of the coolant at atmospheric pressure) while being held at apressure greater than atmospheric pressure. In other words, the coolantcan be a subcooled liquid. Embodiments described herein includere-cooling by allowing a portion of the coolant to escape the higherpressure flow system and enter an evaporation vessel venting to theatmosphere. The coolant at atmospheric pressure accumulates in theevaporation vessel, boils, and maintains a temperature near theatmospheric boiling point of the coolant. For example, LN would boil atabout 77.4 K in atmospheric pressure (near sea level). Heat from thesubcooled high-pressure coolant can then transfer to the boiling coolantvia a heat exchanger or a heat exchange interface. This heat transfercan be via conduction and/or a forced convection mechanism.

Advantages of such a system allow for cooling without the use ofrefrigeration units and lower capital costs. In some embodiments, acooling system can be operated without external power input. In someembodiments, systems can be placed at high voltage and supported off ofa support tower by dielectric insulators. In some embodiments, thecooling system can use local external power harvested inductively from ahigh voltage power conductor or delivered to the station from anexternal power source. As an example, the external power source caninclude a local photovoltaic or thermoelectric energy generation device.In some embodiments, control power can be delivered to the coolingsystem wirelessly. Reduced complexity in relation to systems withrefrigeration allows for more units to be placed along a powertransmission line. Embodiments described herein can be used in tandemwith systems described in U.S. provisional patent application No.63/115,140, titled “Suspended Superconducting Transmission Lines,” filedNov. 18, 2020 (“the '140 application”), which is hereby incorporated byreference in its entirety. Although functional elements are listedseparately herein, it may be advantageous to combine two or morefunctions into one element. For example, in some embodiments, a coolingsystem can include a TIJ and a region vented to atmospheric pressure toboil coolant.

In some embodiments, LN enters a cable near 77.4 K and pressures above 1atmosphere. The LN is therefore subcooled and not boiling. In someembodiments, the LN entering the cable can be pressurized either by pumpor by industry standard vaporizer. The entry and exit pressuresdetermine the flow rate of liquid, or the flow rate from the pumpdetermines the entry pressure. Cooling of the inflowing LN to near 77.4K is achieved by passing the LN through a heat exchanger immersed in aseparate bath of boiling LN venting to the atmosphere. In someembodiments, the system for providing LN at the required pressure, flowrate and temperature is termed a ‘conditioning unit’.

The flowing, subcooled LN warms as it travels along the cable. Theallowed temperature rise is typically smaller (2 K) than in existingstate of art (7 K) and it remains sub-cooled. Consequently, after somedistance (typically between 200 m and 1 km) a re-cooling of thesubcooled LN is desired, typically from 79K to 77K.

In some embodiments, the remaining high pressure subcooled, but “warm,”flowing LN passes through a heat exchanger cooled by the boiling LN. Insome embodiments, the amount of LN flowing into the evaporation vesselcan be controlled to maintain a liquid level sufficient to submerge theheat exchanger but not so as to overflow. Heat from the ‘warm’ LN flowis transferred to the heat exchanger by forced convective heat transfer,and the form and surface of the heat exchanger may be optimized as wellknown in the art. The heat is then transferred to the boiling LN byboiling heat transfer and the form and surface of the heat exchangerexposed to boiling LN may be optimized for boiling heat transfer as wellknown in the art.

In some embodiments, the cold side of the heat exchanger cannot be at atemperature below the boiling temperature of LN under atmosphericpressure. As a consequence, the temperature of the flowing LN, and hencethe operating temperature of the superconductor, is typically above theboiling point of LN at atmospheric pressure. This is in contrast topreviously implemented cooling schemes. Consequently, more re-coolingstations may be desired for a given power line length. However, withstrategic re-cooling station spacing and acceptable inlet pressure,power lines over 100 km long can be constructed with a single LN supplypoint.

At each re-cooling station, a fraction of the flowing LN is removed fromthe flow to cool the remainder. Consequently, the mass flow ratedecreases along the cable.

FIG. 1 is a block diagram showing components of a cooling system 100,according to an embodiment. The cooling system 100 includes a coolanttransmitter 110, an evaporation vessel 130, and a pressure reducer 140.The solid lines indicate fluidic couplings, while the dotted lineindicates an optional fluidic coupling. More specifically, fluid canflow directly between the coolant transmitter 110 and the pressurereducer 140, and fluid can flow directly between the evaporation vessel130 and the pressure reducer 140. In some embodiments, fluid can flowdirectly between the evaporation vessel 130 and the coolant transmitter110. In some embodiments, there is no fluidic coupling at an interfacebetween the evaporation vessel 130 and the coolant transmitter 110(i.e., no fluidic coupling at an interface without the pressure reducer140 as an intermediary). In other words, while the evaporation vessel130 would be fluidically coupled to the coolant transmitter 110 via thepressure reducer 140, there would be no direct fluidic coupling at aninterface between the coolant transmitter 110 and the evaporation vessel130. An example of such a situation is if the coolant transmitterincludes a shell and tube heat exchanger, and fluid flows on the tubeside through the evaporation vessel 130 while fluid flows on the shellside through the coolant transmitter 110. The coolant transmitter 110 isdirectly fluidically coupled to the pressure reducer 140 and theevaporation vessel 130 is directly fluidically coupled to the coolanttransmitter 110. A coolant flows through the cooling system 100 and thecomponents thereof. In some embodiments, the coolant can include LN,liquid helium, liquid neon, liquid air, or any combination thereof.

In use, the coolant flows through the cooling system 100 via the coolanttransmitter 110 at a pressure greater than atmospheric pressure. In thecoolant transmitter 110, the coolant is subcooled and not boiling, butwarmer than the boiling point of the coolant at atmospheric pressure(also referred to herein as “atmospheric boiling point”). A portion ofthe coolant is diverted away from the coolant transmitter 110 and entersthe evaporation vessel 130 via the pressure reducer 140. In theevaporation vessel 130, the coolant can be exposed to atmospheric ornear atmospheric pressure, where the coolant boils while maintaining atemperature at the atmospheric boiling point or near the atmosphericboiling point of the coolant. Heat is then transferred from the boilingcoolant in the evaporation vessel 130 to the subcooled liquid coolant inthe coolant transmitter 110. The subcooled liquid coolant in the coolanttransmitter 110 is cooled to the atmospheric boiling point or near theatmospheric boiling point of the coolant.

In some embodiments, multiple cooling systems 100 can be placed along alength of a power transmission line at regular or irregular intervals.In some embodiments, the intervals can be at least about 200 m, at leastabout 300 m, at least about 400 m, at least about 500 m, at least about600 m, at least about 700 m, at least about 800 m, at least about 900 m,at least about 1 km, at least about 1.5 km, at least about 2 km, atleast about 2.5 km, at least about 3 km, at least about 3.5 km, at leastabout 4 km, or at least about 4.5 km. In some embodiments, the intervalscan be no more than about 5 km, no more than about 4.5 km, no more thanabout 4 km, no more than about 3.5 km, no more than about 3 km, no morethan about 2.5 km, no more than about 2 km, no more than about 1.5 km,no more than about 1 km, no more than about 900 m, no more than about800 m, no more than about 700 m, no more than about 600 m, no more thanabout 500 m, no more than about 400 m, or no more than about 300 m.Combinations of the above-reference intervals for placement of thecooling systems 100 are also possible (e.g., at least about 200 m and nomore than about 5 km or at least about 500 m and no more than about 1km), inclusive of all values and ranges therebetween. In someembodiments, the intervals can be about 200 m, about 300 m, about 400 m,about 500 m, about 600 m, about 700 m, about 800 m, about 900 m, about 1km, about 1.5 km, about 2 km, about 2.5 km, about 3 km, about 3.5 km,about 4 km, about 4.5 km, or about 5 km.

In some embodiments, the coolant transmitter 110 can include a layer ofinsulation (e.g., a TIJ). In some embodiments, the evaporation vessel130 can include a layer of insulation. In some embodiments, the pressurereducer 140 can include a layer of insulation.

The mass flow rate of coolant into the cooling system 100 (i.e., via thecoolant transmitter 110) depends on the allowed temperature rise in asection (i.e., interval) of the power transmission line, the heat to beremoved in each section, and the length of the section, and the specificheat capacity of the coolant. Equation (1) below summarizes thisrelationship.

$\begin{matrix}{M_{in} = \frac{QL}{\Delta TC}} & (1)\end{matrix}$

Where:

M_(in) is the mass flow rate of coolant (kg/s)

Q is the amount of heat to be removed in each section (W/m)

L is the length of a section (m)

ΔT is the allowed temperature rise in a section (K)

C is the specific heat capacity of the coolant (J/kg-K)

Coolant can flow through the evaporation vessel 130. If the evaporationvessel 130 is vented to atmospheric pressure, the temperature of theevaporation vessel 130 will be maintained at the local boiling point ofthe coolant (e.g., 77.4 K for LN at sea level). In some embodiments, theliquid level in the evaporation vessel 130 can be maintained by allowingsome of the coolant to flow from the coolant transmitter 110 to theevaporation vessel 130 via an exit stream conduit (not shown). The exitstream conduit can include an intermediary stream between the coolanttransmitter 110 and the pressure reducer 140. A fraction of the coolantrunning through the coolant transmitter 110 is diverted to theevaporation vessel 130 (e.g., via the exit stream conduit and thepressure reducer 140).

The fraction of coolant that flows through the coolant transmitter 110that is diverted to the evaporation vessel 130 can be calculatedaccording to:

$\begin{matrix}{{f = {\frac{dM}{M_{in}} = \frac{\Delta TC}{\gamma}}},} & (2)\end{matrix}$

where:

f is the fraction of coolant flowing through the coolant transmitter 110that is diverted to the evaporation vessel 130

M_(in) is the mass flow rate of coolant (kg/s), as calculated inEquation (1)

ΔT is the temperature decrease to be achieved in the transfer of heatfrom the coolant in the evaporation vessel 130 to the coolant in thecoolant transmitter 110 (K).

γ is the latent heat of boiling (J/kg)

C is the specific heat capacity of the coolant (J/kg-K)

In some embodiments, ΔT can be the same or substantially similar to ΔTcalculated in Equation (1). In other words, the cooling achieved intransferring heat from the evaporation vessel 130 to the coolanttransmitter 110 can offset the temperature increase allowed in a sectionof the coolant transmitter 110.

In some embodiments, the weight percentage of coolant that is divertedfrom the coolant transmitter 110 to the evaporation vessel 130 can be atleast about 0.5 wt %, at least about 1 wt %, at least about 1.5 wt %, atleast about 2 wt %, at least about 2.5 wt %, at least about 3 wt %, atleast about 3.5 wt %, at least about 4 wt %, at least about 4.5 wt %, atleast about 5 wt %, at least about 5.5 wt %, at least about 6 wt %, atleast about 6.5 wt %, at least about 7 wt %, at least about 7.5 wt %, atleast about 8 wt %, at least about 8.5 wt %, at least about 9 wt %, orat least about 9.5 wt %. In some embodiments, the weight percentage ofcoolant that is diverted from the coolant transmitter 110 to theevaporation vessel 130 can be no more than about 10 wt %, no more thanabout 9.5 wt %, no more than about 9 wt %, no more than about 8.5 wt %,no more than about 8 wt %, no more than about 7.5 wt %, no more thanabout 7 wt %, no more than about 6.5 wt %, no more than about 6 wt %, nomore than about 5.5 wt %, no more than about 5 wt %, no more than about4.5 wt %, no more than about 4 wt %, no more than about 3.5 wt %, nomore than about 3 wt %, no more than about 2.5 wt %, no more than about2 wt %, no more than about 1.5 wt %, or no more than about 1 wt %.Combinations of the above-referenced ranges for the weight percentage ofcoolant diverted from the coolant transmitter 110 to the evaporationvessel 130 are also possible (e.g., at least about 0.5 wt % and no morethan about 10 wt % or at least about 1 wt % and no more than about 5 wt%), inclusive of all values and ranges therebetween. In someembodiments, the weight percentage of coolant that is diverted from thecoolant transmitter 110 to the evaporation vessel 130 can be about 0.5wt %, about 1 wt %, about 1.5 wt %, about 2 wt %, about 2.5 wt %, about3 wt %, about 3.5 wt %, about 4 wt %, about 4.5 wt %, about 5 wt %,about 5.5 wt %, about 6 wt %, about 6.5 wt %, about 7 wt %, about 7.5 wt%, about 8 wt %, about 8.5 wt %, about 9 wt %, about 9.5 wt %, or about10 wt %.

In some embodiments, coolant can be diverted from the coolanttransmitter 110 to the evaporation vessel 130 at a rate of at leastabout 0.1 L/min, at least about 0.2 L/min, at least about 0.3 L/min, atleast about 0.4 L/min, at least about 0.5 L/min, at least about 0.6L/min, at least about 0.7 L/min, at least about 0.8 L/min, at leastabout 0.9 L/min, at least about 1 L/min, at least about 2 L/min, atleast about 3 L/min, at least about 4 L/min, at least about 5 L/min, atleast about 6 L/min, at least about 7 L/min, at least about 8 L/min, orat least about 9 L/min, or about 10 L/min. In some embodiments, coolantcan be diverted from the coolant transmitter 110 to the evaporationvessel 130 at a rate no more than about 10 L/min, no more than about 9L/min, no more than about 8 L/min, no more than about 7 L/min, no morethan about 6 L/min, no more than about 5 L/min, no more than about 4L/min, no more than about 3 L/min, no more than about 2 L/min, no morethan about 1 L/min, no more than about 0.9 L/min, no more than about 0.8L/min, no more than about 0.7 L/min, no more than about 0.6 L/min, nomore than about 0.5 L/min, no more than about 0.4 L/min, no more thanabout 0.3 L/min, or no more than about 0.2 L/min. Combinations of theabove-referenced ranges for the amount of coolant diverted from thecoolant transmitter 110 to the evaporation vessel 130 are also possible(e.g., at least about 0.1 L/min and no more than about 10 L/min or atleast about 1 L/min and no more than about 5 L/min), inclusive of allvalues and ranges therebetween. In some embodiments, coolant can bediverted from the coolant transmitter 110 to the evaporation vessel 130at a rate of about 0.1 L/min, about 0.2 L/min, about 0.3 L/min, about0.4 L/min, about 0.5 L/min, about 0.6 L/min, about 0.7 L/min, about 0.8L/min, about 0.9 L/min, about 1 L/min, about 2 L/min, about 3 L/min,about 4 L/min, about 5 L/min, about 6 L/min, about 7 L/min, about 8L/min, about 9 L/min, or about 10 L/min. In some embodiments, the flowrate of coolant to the evaporation vessel 130 and/or the fraction ofcoolant diverted from the coolant transmitter 110 to the evaporationvessel 130 and/or the liquid coolant level can be controlled by a levelsensor (not shown) disposed in the evaporation vessel 130.

In some embodiments, the coolant transmitter 110 can be maintained at agauge pressure of at least about 1 bar, at least about 2 bar, at leastabout 3 bar, at least about 4 bar, at least about 5 bar, at least about6 bar, at least about 7 bar, at least about 8 bar, at least about 9 bar,at least about 10 bar, at least about 15 bar, at least about 20 bar, atleast about 25 bar, at least about 30 bar, at least about 35 bar, atleast about 40 bar, or at least about 45 bar. In some embodiments, thecoolant transmitter 110 can be maintained at a gauge pressure of no morethan about 50 bar, no more than about 45 bar, no more than about 40 bar,no more than about 35 bar, no more than about 30 bar, no more than about25 bar, no more than about 20 bar, no more than about 15 bar, no morethan about 10 bar, no more than about 9 bar, no more than about 8 bar,no more than about 7 bar, no more than about 6 bar, no more than about 5bar, no more than about 4 bar, no more than about 3 bar, or no more thanabout 2 bar. Combinations of the above-referenced gauge pressures in thecoolant transmitter 110 are also possible (e.g., at least about 1 barand no more than about 50 bar or at least about 10 bar and no more thanabout 30 bar), inclusive of all values and ranges therebetween. In someembodiments, the coolant transmitter 110 can be maintained at a gaugepressure of about 1 bar, about 1 bar, about 2 bar, about 3 bar, about 4bar, about 5 bar, about 6 bar, about 7 bar, about 8 bar, about 9 bar,about 10 bar, about 15 bar, about 20 bar, about 25 bar, about 30 bar,about 35 bar, about 40 bar, about 45 bar, or about 50 bar. In someembodiments, the pressure in the coolant transmitter 110 can bemaintained via a pump, a booster pump, a compressor, a centrifugal pump,or any combination thereof.

In some embodiments, the cooling system 100 can limit the increase intemperature of the coolant in the coolant transmitter 110 (i.e., ΔT fromEquation (1) above) to no more than about 10 K, no more than about 9 K,no more than about 8 K, no more than about 7 K, no more than about 6 K,no more than about 5 K, no more than about 4 K, no more than about 3 K,no more than about 2 K, no more than about 1 K, no more than about 0.9K, no more than about 0.8 K, no more than about 0.7 K, no more thanabout 0.6 K, no more than about 0.5 K, no more than about 0.4 K, no morethan about 0.3 K, no more than about 0.2 K, or no more than about 0.1 K,inclusive of all values and ranges therebetween.

In some embodiments, the cooling system 100 can limit the temperature ofthe coolant in the coolant transmitter 110 to be no more than about 10K, no more than about 9 K, no more than about 8 K, no more than about 7K, no more than about 6 K, no more than about 5 K, no more than about 4K, no more than about 3 K, no more than about 2 K, no more than about 1K, no more than about 0.9 K, no more than about 0.8 K, no more thanabout 0.7 K, no more than about 0.6 K, no more than about 0.5 K, no morethan about 0.4 K, no more than about 0.3 K, no more than about 0.2 K, orno more than about 0.1 K greater than the atmospheric (i.e., at 760mmHg) boiling point of the coolant, inclusive of all values and rangestherebetween.

In some embodiments, the evaporation vessel 130 can be vented toatmospheric pressure. In some embodiments, the evaporation vessel 130can be maintained at or near atmospheric pressure. In some embodiments,the evaporation vessel 130 can be maintained at a pressure lower thanthe pressure of the coolant transmitter 110. In some embodiments, theevaporation vessel 130 can be maintained at a pressure lower than thepressure of the coolant transmitter 110 by at least about 1 bar, atleast about 2 bar, at least about 3 bar, at least about 4 bar, at leastabout 5 bar, at least about 6 bar, at least about 7 bar, at least about8 bar, at least about 9 bar, at least about 10 bar, at least about 15bar, at least about 20 bar, at least about 25 bar, at least about 30bar, at least about 35 bar, at least about 40 bar, or at least about 45bar. In some embodiments, the evaporation vessel 130 can be maintainedat a pressure lower than the pressure of the coolant transmitter 110 byno more than about 50 bar, no more than about 45 bar, no more than about40 bar, no more than about 35 bar, no more than about 30 bar, no morethan about 25 bar, no more than about 20 bar, no more than about 15 bar,no more than about 10 bar, no more than about 9 bar, no more than about8 bar, no more than about 7 bar, no more than about 6 bar, no more thanabout 5 bar, no more than about 4 bar, no more than about 3 bar, or nomore than about 2 bar. Combinations of the above referenced differencesbetween the pressure of the evaporation vessel 130 and the coolanttransmitter 110 are also possible (e.g., at least about 1 bar and nomore than about 50 bar or at least about 15 bar and no more than about25 bar), inclusive of all values and ranges therebetween. In someembodiments, the evaporation vessel 130 can be maintained at a pressurelower than the pressure of the coolant transmitter 110 by about 1 bar,about 2 bar, about 3 bar, about 4 bar, about 5 bar, about 6 bar, about 7bar, about 8 bar, about 9 bar, about 10 bar, about 15 bar, about 20 bar,about 25 bar, about 30 bar, about 35 bar, about 40 bar, about 45 bar, orabout 50 bar.

In some embodiments, the evaporation vessel 130 can include a heatexchanger (not shown). For example, the evaporation vessel 130 caninclude one or more tubes that act as a tube side of a shell and tubeheat exchanger, while the coolant transmitter 110 can include a portionthat acts as a shell running along the outside of the tubes in theevaporation vessel 130. In some embodiments, the evaporation vessel 130can be a heat exchanger. In some embodiments, the evaporation vessel 130can be a spiral tube heat exchanger. In some embodiments, theevaporation vessel 130 can be contained inside the coolant transmitter110.

In some embodiments, the cooling system 100 can include a heat exchangerat an interface between the evaporation vessel 130 and the coolanttransmitter 110. Coolant can circulate between the coolant transmitter110 and the heat exchanger on a first side of the heat exchanger, andcoolant can flow between the evaporation vessel 130 and the heatexchanger on a second side of the heat exchanger. In some embodiments,the first side of the heat exchanger can be a shell side. In someembodiments, the first side of the heat exchanger can be a tube side. Insome embodiments, the second side of the heat exchanger can be a shellside. In some embodiments, the second side of the heat exchanger can bea tube side. In some embodiments, the heat exchanger can be a plate-finheat exchanger. In some embodiments, the evaporation vessel 130 can beenclosed in a TIJ to prevent boil-off of coolant.

Coolant flows from the coolant transmitter 110 to the evaporation vessel130 via the pressure reducer 140. In some embodiments, the coolant canflow from the coolant transmitter 110 to the evaporation vessel 130 viamultiple conduits. In some embodiments, the coolant can flow from thecoolant transmitter 110 to the evaporation vessel 130 via 1, 2, 3, 4, 5,6, 7, 8, 9, 10 or more conduits. In some embodiments, the pressurereducer 140 can include an orifice. In some embodiments, the pressurereducer 140 can include multiple orifices. In some embodiments, thepressure reducer 140 can include a throttle. In some embodiments, thepressure reducer 140 can include a valve. In some embodiments, thepressure reducer 140 can include multiple valves.

In some embodiments, the pressure reducer 140 can maintain a pressuredifference between the coolant transmitter 110 and the evaporationvessel 130 of at least about 1 bar, at least about 2 bar, at least about3 bar, at least about 4 bar, at least about 5 bar, at least about 6 bar,at least about 7 bar, at least about 8 bar, at least about 9 bar, atleast about 10 bar, at least about 15 bar, at least about 20 bar, atleast about 25 bar, at least about 30 bar, at least about 35 bar, atleast about 40 bar, or at least about 45 bar. In some embodiments, thepressure reducer 140 can maintain a pressure difference between thecoolant transmitter 110 and the evaporation vessel 130 of no more thanabout 50 bar, no more than about 45 bar, no more than about 40 bar, nomore than about 35 bar, no more than about 30 bar, no more than about 25bar, no more than about 20 bar, no more than about 15 bar, no more thanabout 10 bar, no more than about 9 bar, no more than about 8 bar, nomore than about 7 bar, no more than about 6 bar, no more than about 5bar, no more than about 4 bar, no more than about 3 bar, or no more thanabout 2 bar. Combinations of the above-referenced pressure gradientsmaintained by the pressure reducer 140 are also possible (e.g., at leastabout 1 bar and no more than about 50 bar or at least about 10 bar andno more than about 30 bar), inclusive of all values and rangestherebetween. In some embodiments, the pressure reducer 140 can maintaina pressure difference between the coolant transmitter 110 and theevaporation vessel 130 of about 1 bar, about 2 bar, about 3 bar, about 4bar, about 5 bar, about 6 bar, about 7 bar, about 8 bar, about 9 bar,about 10 bar, about 15 bar, about 20 bar, about 25 bar, about 30 bar,about 35 bar, about 40 bar, about 45 bar, or about 50 bar.

FIG. 2 illustrates a cooling system 200, according to an embodiment. Thecooling system 200 includes a coolant transmitter 210, an exit streamconduit 220, an evaporation vessel 230, a throttle 241, a heat exchanger250, an exit vent 256, and a level sensor 260. In some embodiments, thecoolant transmitter 210 and the evaporation vessel 230 can be the sameor substantially similar to the coolant transmitter 110 and theevaporation vessel 130, as described above with reference to FIG. 1.Thus, certain aspects of the coolant transmitter 210 and the evaporationvessel 230 are not described in greater detail herein. Also shown inFIG. 2 is a coolant 10. As shown, the coolant 10 flows as a liquid alongliquid lines L and as a vapor along vapor lines V.

In some embodiments, the coolant transmitter 210 can be coupled to apower transmission line at an initial end of the coolant transmitter 210and at a terminal end of the coolant transmitter 210. The coolant 10moves through the coolant transmitter 210 as a liquid. In someembodiments, the coolant transmitter 210 can include a pipe, multiplepipes, conduits, or any combination thereof. In some embodiments, thecoolant transmitter 210 can include an insulation layer. In someembodiments, the coolant transmitter 210 can run underground.

The exit stream conduit 220 diverts a portion of the coolant 10 from thecoolant transmitter 210 to the evaporation vessel 230. The exit streamconduit 220 and the throttle 241 fluidically couple the coolanttransmitter 210 to the evaporation vessel 230. In some embodiments, theopening of the throttle 241 can control the flow of the coolant 10through the exit stream conduit 220. In some embodiments, the levelsensor 260 can control the opening of the throttle 241. In other words,the amount of the coolant 10 that is diverted from the coolanttransmitter 210 can be controlled based on how much coolant is in theevaporation vessel 230. In some embodiments, the exit stream conduit 220can include a thermal insulation layer.

The coolant 10 in the evaporation vessel 230 boils and draws heat fromthe coolant transmitter 210 via the heat exchanger 250. In someembodiments, the evaporation vessel 230 can be vented (i.e., via theexit vent 256) to the atmosphere and be held at atmospheric pressure. Insome embodiments, the evaporation vessel 230 can be vented to a pressureabove atmospheric pressure. In some embodiments, the evaporation vessel230 can be vented to a pipe that transports vapor to a further heatexchanger (not shown) that warms the vapor to an ambient temperatureprior to venting. In some embodiments, the evaporation vessel 230 caninclude a layer of insulation disposed around the outside of theevaporation vessel 230. In some embodiments, a portion of the coolant 10can be captured after boiling from the evaporation vessel 230 for lateruse.

In some embodiments, the evaporation vessel 230 can have a volume of atleast about 0.001 m³, at least about 0.002 m³, at least about 0.003 m³,at least about 0.004 m³, at least about 0.005 m³, at least about 0.006m³, at least about 0.007 m³, at least about 0.008 m³, at least about0.009 m³, at least about 0.01 m³, at least about 0.02 m³, at least about0.03 m³, at least about 0.04 m³, at least about 0.05 m³, at least about0.06 m³, at least about 0.07 m³, at least about 0.08 m³, at least about0.09 m³, at least about 0.1 m³, at least about 0.2 m³, at least about0.3 m³, at least about 0.4 m³, at least about 0.5 m³, at least about 0.6m³, at least about 0.7 m³, at least about 0.8 m³, at least about 0.9 m³,at least about 1 m³, at least about 2 m³, at least about 3 m³, at leastabout 4 m³, at least about 5 m³, at least about 6 m³, at least about 7m³, at least about 8 m³, at least about 9 m³, at least about 10 m³, atleast about 20 m³, at least about 30 m³, at least about 40 m³, or atleast about 50 m³. In some embodiments, the evaporation vessel 230 canhave a volume of no more than about 50 m³, no more than about 40 m³, nomore than about 30 m³, no more than about 20 m³, no more than about 10m³, no more than about 9 m³, no more than about 8 m³, no more than about7 m³, no more than about 6 m³, no more than about 5 m³, no more thanabout 4 m³, no more than about 3 m³, no more than about 2 m³, no morethan about 1 m³, no more than about 0.9 m³, no more than about 0.8 m³,no more than about 0.7 m³, no more than about 0.6 m³, no more than about0.5 m³, no more than about 0.4 m³, no more than about 0.3 m³, no morethan about 0.2 m³, no more than about 0.1 m³, no more than about 0.09m³, no more than about 0.08 m³, no more than about 0.07 m³, no more thanabout 0.06 m³, no more than about 0.05 m³, no more than about 0.04 m³,no more than about 0.03 m³, no more than about 0.02 m³, no more thanabout 0.01 m³, no more than about 0.009 m³, no more than about 0.008 m³,no more than about 0.007 m³, no more than about 0.006 m³, no more thanabout 0.005 m³, no more than about 0.004 m³, no more than about 0.003m³, no more than about 0.002 m³, or no more than about 0.001 m³.Combinations of the above-referenced volumes of the evaporation vessel230 are also possible (e.g., at least about 0.001 m³ and no more thanabout 50 m3, or at least about 0.1 m³ and no more than about 50 m³),inclusive of all values and ranges therebetween. In some embodiments,the evaporation vessel 230 can have a volume of about 0.1 m³, about 0.2m³, about 0.3 m³, about 0.4 m³, about 0.5 m³, about 0.6 m³, about 0.7m³, about 0.8 m³, about 0.9 m³, about 1 m³, about 2 m³, about 3 m³,about 4 m³, about 5 m³, about 6 m³, about 7 m³, about 8 m³, about 9 m³,about 10 m³, about 20 m³, about 30 m³, about 40 m³, or about 50 m³.

The throttle 241 acts as a flow regulator at an interface between theexit stream conduit 220 and the evaporation vessel 230. In someembodiments, the throttle 241 can act as a pressure regulator orpressure reducer at an interface between the exit stream conduit 220 andthe evaporation vessel 230. In some embodiments, the throttle 241 canhave the same or substantially similar properties to the pressurereducer 140, as described above with reference to FIG. 1. In someembodiments, the cooling system 200 can include an orifice or multipleorifices at the interface between the exit stream conduit 220 and theevaporation vessel 230. In some embodiments, the throttle 241 caninclude a valve. In some embodiments, the throttle 241 can includemultiple valves.

The heat exchanger 250 has a first side fluidically coupled to thecoolant transmitter 210 and a second side fluidically coupled to theevaporation vessel 230. In some embodiments, the heat exchanger 250 caninclude a shell and tube heat exchanger. In some embodiments, the firstside can be a shell side of the shell and tube heat exchanger. In someembodiments, the first side can be a tube side of the shell and tubeheat exchanger. In some embodiments, the second side can be a shell sideof the shell and tube heat exchanger. In some embodiments, the secondside can be a tube side of the shell and tube heat exchanger. In someembodiments, the heat exchanger 250 can include a parallel flow heatexchanger, a counter flow heat exchanger, a finned tubular heatexchanger, a single pass heat exchanger, a two pass heat exchanger, aU-tube heat exchanger, a compact heat exchanger, a plate-fin heatexchanger, a spiral tube heat exchanger, or any combination thereof. Insome embodiments, the heat exchanger 250 can include a surface enhancedfor forced convective heat transfer.

In some embodiments, the level sensor 260 can communicate with thethrottle 241 to control the opening of the throttle 241. In someembodiments, the level sensor 260 can include an optical sensor, acapacitive sensor, a conductive sensor, a diaphragm sensor, a floatsensor, or any combination thereof.

FIG. 3 illustrates a cooling system 300, according to an embodiment. Thecooling system 300 includes a coolant transmitter 310 (divided into afirst portion 310 a and a second portion 310 b), an exit stream conduit320, an evaporation vessel 330, a pressure regulator 340 (e.g., a floatvalve), a heat exchanger 350, an exit vent 356 a level sensor 360, and aTIJ 370.

In some embodiments, the coolant transmitter 310, the exit streamconduit 320, the evaporation vessel 330, the heat exchanger 350, and thelevel sensor 360 can be the same or substantially similar to the coolanttransmitter 210, the exit stream conduit 220, the evaporation vessel230, the heat exchanger 250, and the level sensor 260, as describedabove with reference to FIG. 2. In some embodiments, the pressureregulator 340 can be the same or substantially similar to the pressurereducer 140, as described above with reference to FIG. 1. Thus, certainaspects of the coolant transmitter 310, the exit stream conduit 320, theevaporation vessel 330, the pressure regulator 340, the heat exchanger350, and the level sensor 360 are not described in greater detailherein. As shown, the coolant 10 flows as a liquid along arrows L and asa vapor along arrow V (via exit vent 356).

The coolant 10 is open to atmospheric pressure via the exit vent 356,and will consequently boil at about 77.4 K due to heat from the coolant10 in the coolant transmitter 310. In some embodiments, the coolingsystem 300 can be placed on top of the poles supporting an overheadsuperconducting power transmission line. In some embodiments, thecooling system 300 can be placed in an underground vault for use duringoperation of an underground superconducting power transmission line.

As shown, the coolant transmitter 310 is divided into the first portion310 a and the second portion 310 b. The first portion 310 a transportsthe coolant 10 from an initial end of the coolant transmitter 310 to theheat exchanger 350. The second portion 310 b transports the coolant 10from the heat exchanger 350 to the terminal end of the coolanttransmitter 310. As shown, the heat exchanger 350 is fully submersed inthe coolant 10 boiling in the evaporation vessel 330. In someembodiments, the heat exchanger 350 can be partially submersed in thecoolant 10 boiling in the evaporation vessel 330. As shown, the heatexchanger 350 has a spiral shape. In some embodiments, the heatexchanger 350 can be formulated to maximize heat exchange between thecoolant 10 boiling in the evaporation vessel 330 and the coolant 10flowing through the heat exchanger 350.

As shown, the level sensor 360 is physically coupled to the pressureregulator 340. In some embodiments, the level sensor 360 can bephysically coupled to an inner wall of the evaporation vessel 330.

As shown, the TIJ 370 is disposed around the outside of the evaporationvessel 330. In some embodiments, the TIJ 370 can aid in minimizing boiloff of the coolant. In some embodiments, the TIJ 370 can includefiberglass, polyurethane, down insulation, polyester, fibers, polyfill,or any combination thereof. In some embodiments, the TIJ 370 can includea dual wall vacuum jacket that is optionally supplemented by one or morelayers of additional insulative materials (e.g., fiberglass,polyurethane, down insulation, polyester, fibers, polyfill, or anycombination thereof). In some embodiments, the dual wall vacuum jacketcan be disposed around the outside of the evaporation vessel 330 withoutadditional layers of insulative materials. In some embodiments, the TIJ370 can have a thickness of at least about 1 mm, at least about 2 mm, atleast about 3 mm, at least about 4 mm, at least about 5 mm, at leastabout 6 mm, at least about 7 mm, at least about 8 mm, at least about 9mm, at least about 1 cm, at least about 2 cm, at least about 3 cm, atleast about 4 cm, at least about 5 cm, at least about 6 cm, at leastabout 7 cm, at least about 8 cm, at least about 9 cm, at least about 10cm, at least about 20 cm, at least about 30 cm, at least about 40 cm, atleast about 50 cm, at least about 60 cm, at least about 70 cm, at leastabout 80 cm, or at least about 90 cm. In some embodiments, the TIJ 370can have a thickness of no more than about 1 m, no more than about 90cm, no more than about 80 cm, no more than about 70 cm, no more thanabout 60 cm, no more than about 50 cm, no more than about 40 cm, no morethan about 30 cm, no more than about 20 cm, no more than about 10 cm, nomore than about 9 cm, no more than about 8 cm, no more than about 7 cm,no more than about 6 cm, no more than about 5 cm, no more than about 4cm, no more than about 3 cm, no more than about 2 cm, no more than about1 cm, no more than about 9 mm, no more than about 8 mm, no more thanabout 7 mm, no more than about 6 mm, no more than about 5 mm, no morethan about 4 mm, no more than about 3 mm, or no more than about 2 mm.Combinations of the above-referenced thicknesses of the TIJ 370 are alsopossible (e.g., at least about 1 mm and no more than about 1 m or atleast about 1 cm and no more than about 20 cm), inclusive of all valuesand ranges therebetween. In some embodiments, the TIJ 370 can have athickness of about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm,about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 1 cm, about 2 cm,about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm,about 9 cm, about 10 cm, about 20 cm, about 30 cm, about 40 cm, about 50cm, about 60 cm, about 70 cm, about 80 cm, about 90 cm, or about 1 m.

FIG. 4 illustrates a cooling system 400, according to an embodiment. Asshown, the cooling system 400 includes a coolant transmitter 410(divided into a first portion 410 a and a second portion 410 b), an exitstream conduit 420, an evaporation vessel 430, an orifice 442, a heatexchanger 450, an exit vent 456, a TIJ 470, and, optionally, a levelsensor (not shown). In some embodiments, the coolant transmitter 410,the exit stream conduit 420, the evaporation vessel 430, the heatexchanger 450, the exit vent 456, the TIJ 470, and the optional levelsensor can be the same or substantially similar to the coolanttransmitter 310, the exit stream conduit 320, the evaporation vessel330, the heat exchanger 350, the exit vent 356, the TIJ 370, and thelevel sensor 360 as described above with reference to FIG. 3. Thus,certain aspects of the coolant transmitter 410, the exit stream conduit420, the evaporation vessel 430, the heat exchanger 450, the TIJ 470,and the level sensor are not described in greater detail herein. Asshown, the coolant 10 flows as a liquid along liquid lines L and as avapor along vapor lines V.

As shown, the orifice 442 regulates flow of the coolant 410 between theexit stream conduit 420 and the evaporation vessel 430. The orifice 442also acts as a pressure regulator, regulating the pressure differencebetween the exit stream conduit 420 and the evaporation vessel 430. Insome embodiments, the orifice 442 can include one opening. In someembodiments, the orifice 442 can include multiple openings (e.g., agrate). In some embodiments, the orifice 442 can include otherimpediments/impedance to fluid flow, such as a valve or a throttle. Insome embodiments, the orifice 442 can be included in the cooling system400 without valves or level sensors disposed in the evaporation vessel430. In some embodiments, the pressure in the coolant transmitter 410can change along the length of the coolant transmitter 410 due tohydrostatic head loss. Therefore, the size of the orifice 442 and/or thenumber of openings included in the orifice 442 can vary with locationalong the coolant transmitter 410. For example, if the orifice 442 is ata first location along the coolant transmitter 410, it can have a firstdiameter. If the orifice 442 is at a second location along the coolanttransmitter 410, the second location downstream of the first location,the orifice 442 can have a second diameter larger than the firstdiameter. Since the pressure is lower at the second location, theorifice 442 would be larger at the second location to deliver similarflow rate of coolant 10 through the orifice 442. However, flow rateacross the orifice 442 can vary proportionally to the square root of thepressure differential across the orifice 442. Consequently, the diameterof the orifice 442 for a given flow rate at different pressures varieswith the fourth root of the pressure. This is a weak dependence and canallow for a single orifice size to provide adequate flow of the coolant10 over a range of pressures along the coolant transmitter 410. Theamount of cooling employed by the cooling system 400 can be varied bycontrolling inlet pressure and/or flow rate of coolant through thecooling system 400.

FIGS. 5A-5B illustrate a cooling system 500 and various componentsthereof, according to an embodiment. As shown, the cooling system 500includes a coolant transmitter 510 (including a first portion 510 a anda second portion 510 b), an exit stream conduit 520, an evaporationvessel 530, a thermal plate 538, an orifice 542, a heat exchanger 550, aheat exchange region 554, and a TIJ 570. In some embodiments, thecoolant transmitter 510, the first portion 510 a, the second portion 510b, the exit stream conduit 520, the evaporation vessel 530, the orifice542, the heat exchanger 550, and the TIJ 570 can be the same orsubstantially similar to the coolant transmitter 410, the first portion410 a, the second portion 410 b, the exit stream conduit 420, theevaporation vessel 430, the orifice 442, the heat exchanger 450, and theTIJ 470 as described above with reference to FIG. 4. Thus, certainaspects of the coolant transmitter 510, the first portion 510 a, thesecond portion 510 b, the exit stream conduit 520, the evaporationvessel 530, the orifice 542, the heat exchanger 550, and the TIJ 570 arenot described in greater detail herein. As shown, the coolant 10 flowsas a liquid along liquid lines L and as a vapor along vapor lines V.

FIG. 5A shows a cross section of the cooling system 500 while FIG. 5Bshows an external view of the coolant transmitter 510 and theevaporation vessel 530. FIG. 5B shows box A, along which FIG. 5A isviewed. In some embodiments, the cooling system 500 can be suspended onan OH power transmission line conductor, optionally far from supportstructures or support poles. In some embodiments, the cooling system 500can be in an underground vault or conduit as part of an undergroundpower transmission line. In some embodiments, the cooling system 500 canoperate at any angle and move laterally.

The coolant transmitter 510 receives the coolant from a powertransmission line. The coolant transmitter 510 feeds (or is fluidicallycoupled) to an inlet to the heat exchange region 554. The coolanttransmitter 510 is fluidically coupled to the exit stream conduit 520.Coolant from the coolant transmitter 510 flows through the exit streamconduit 520 and exits through the orifice 542 as a vapor stream alongvapor line V. The coolant 10 makes contact with the heat exchanger 550as a vapor, more specifically with the heat exchange region 554. Heat isdrawn from the liquid coolant in the heat exchange region 554 to thethermal plate 538. Heat is then drawn from the thermal plate 538 to thevapor coolant external to and in contact with the thermal plate 538. Insome embodiments, the inclusion of more coils and/or an increase to thesurface area in the heat exchanger 550 can give rise to a moresubstantial transfer of heat. Once the liquid coolant exits the heatexchanger 550, it has reduced in temperature due to the heat transfer tothe coolant vapor at or near atmospheric pressure. In other words, thespraying of the coolant 10 onto the thermal plate 538 and the subsequentboiling thereof (collectively referred to as “spray boiling”) causes theheat to transfer from the liquid coolant in the heat exchanger 550 tothe vapor coolant on the outside of the heat exchanger 550.

As shown, the evaporation vessel 530 includes the thermal plate 538 andis bounded on either side by the TIJ 570. In some embodiments, theevaporation vessel 530 may not include any “walls” bounding theevaporation vessel 530 on either side. In other words, the evaporationvessel 530 can simply refer to an open space or volume into which thecoolant 10 is sprayed and where the sprayed coolant 10 subsequentlyboils. The thermal plate 538 can maximize contact between vapor coolantejected from the exit stream conduit 520 and the heat exchange region554. In some embodiments, vapor coolant can be kept near the heatexchange region 554 and condense, vaporize, and/or boil in closeproximity to the heat exchange region 554 rather than falling away fromthe heat exchange region 554.

The orifice 542 regulates flow of the coolant 10 out of the exit streamconduit 520. In some embodiments, the orifice 542 can also regulate thepressure differential between the exit stream conduit 520 and theevaporation vessel 530. In some embodiments, the orifice 542 can bedesigned to minimize coolant flooding of the heat exchange region 554.In other words, the orifice 542 can be adjustable based on how much ofthe coolant 10 is in close proximity to the heat exchange region 554. Insome embodiments, a level sensor can detect how much of the coolant isin the evaporation vessel 530 and/or in close proximity to the heatexchange region 554.

In some embodiments, the cooling system 500 can operate in a narrowtemperature range (e.g., between about 78K and about 79K), and multiplesuch cooling systems 500 may be placed at close intervals along atransmission line. In some embodiments, the coolant 10 that passesthrough the cooling system 500 can be maintained within a narrowtemperature range, such that the difference between a maximumtemperature and a minimum temperature of the coolant 10 passing throughthe cooling system 500 is no more than about 5 K, no more than about 4K, no more than about 3 K, no more than about 2 K, no more than about 1K, no more than about 0.9 K, no more than about 0.8 K, no more thanabout 0.7 K, no more than about 0.6 K, or no more than about 0.5 K. Insome embodiments, the spray of the coolant 10 through the orifice 542can be continuous or constant. In some embodiments, the orifice 542 canbe sized such that the coolant 10 does not accumulate as a liquid alongoutside surfaces of the heat exchanger 550. In some embodiments, theorifice 542 can be sized such that the coolant 10 does not accumulate asa liquid along any outside surfaces of the cooling system 500. In someembodiments, the cooling system 500 can be vented directly to theatmosphere.

FIG. 6 illustrates a cooling system 600, according to an embodiment. Asshown, the cooling system 600 includes a coolant transmitter 610, anevaporation vessel 630, a pressure regulator 640, and an exit vent 656.In some embodiments, the coolant transmitter 610, the evaporation vessel630, and the pressure regulator 640 can be the same or substantiallysimilar to the coolant transmitter 110, the evaporation vessel 130, andthe pressure reducer 140, as described above with reference to FIG. 1.Thus, certain aspects of the coolant transmitter 610, the evaporationvessel 630, and the pressure regulator 640 are not described in greaterdetail herein. Also shown in FIG. 6 is a coolant 10. As shown, thecoolant 10 flows as a liquid along liquid lines L and as a vapor alongvapor lines V.

In some embodiments, the coolant 10 can enter the coolant transmitter610 from a power transmission line and move through the coolanttransmitter 610 along the liquid lines L. The coolant 10 passes aroundthe outside of the evaporation vessel 630. As shown the evaporationvessel 630 is a spiral tube heat exchanger. The coolant 10 enters theevaporation vessel 630 through the pressure regulator 640. As shown, theevaporation vessel 630 is partially disposed in the coolant transmitter610. In some embodiments, the evaporation vessel 630 can be fullydisposed in the coolant transmitter 610.

In some embodiments, the evaporation vessel 630 can be vented toatmospheric pressure or near atmospheric pressure via the exit vent 656.In some embodiments, heat transfer from the evaporation vessel 630 canbe via forced convective cooling of the coolant 10 surrounding theevaporation vessel 630. As shown, the evaporation vessel 630 is spiralin shape. In some embodiments, the evaporation vessel 630 can includeany shape suitable for heat transfer.

In some embodiments, the coolant transmitter 610 can directly encase atransmission line conductor (not shown). In other words, thetransmission line conductor can run through the coolant transmitter 610.In some embodiments, the cooling system 600 can include asuperconducting cable (not shown) disposed in the coolant transmitter610 and running the length of the coolant transmitter 610. In someembodiments, the cooling system 600 can include a structural tensioncable (not shown) disposed in the coolant transmitter 610 and runningthe length of the coolant transmitter 610. In some embodiments, thetransmission line conductor, the superconducting cable, and/or thestructural tension cable can run through a space surrounded by coolanttransmitter 610.

In some embodiments, the evaporation vessel 630 can be a heat exchangetube that extends along a portion of the length of the coolanttransmitter 610. In some embodiments, the evaporation vessel 630 can bea heat exchange tube that extends along the entire length of the coolanttransmitter 610. In some embodiments, multiple heat exchange tubes canbe disposed along the length of a power transmission line, optionallywith multiple vents along the length of the power transmission line, forperiodic venting. In some embodiments, the multiple heat exchange tubescan be spaced apart from one another. In other embodiments, some or allof the multiple heat exchange tubes can be joined together to form acontinuous chain of heat exchange tubes, to cover some or all of thelength of the power transmission line.

FIG. 7 illustrates a cooling system 700, according to an embodiment. Asshown, the cooling system 700 includes a coolant transmitter 710, anevaporation vessel 730, an orifice 742, and an exit vent 756. In someembodiments, the coolant transmitter 710 and the evaporation vessel 730can be the same or substantially similar to the coolant transmitter 110and the evaporation vessel 130, as described above with reference toFIG. 1. In some embodiments, the orifice 742 can be the same orsubstantially similar to the orifice 442, as described above withreference to FIG. 4. In some embodiments, the exit vent 756 can be thesame or substantially similar to the exit vent 656, as described abovewith reference to FIG. 6. Thus, certain aspects of the coolanttransmitter 710, the evaporation vessel 730, the orifice 742, and theexit vent 756 are not described in greater detail herein. As shown, thecoolant 10 flows as a liquid along liquid lines L and as a vapor alongvapor lines V.

As shown, the coolant 10 flows through the coolant transmitter 710 alongliquid lines L and a portion of the coolant 10 is diverted to theevaporation vessel 730 via the orifice 742. The coolant 10 then flowsthrough the evaporation vessel 730 along vapor lines V. Heat istransferred from the coolant transmitter 710 to the evaporation vessel730. The coolant 10 exits the evaporation vessel 730 via the exit vent756. As shown, the coolant 10 flows through the evaporation vessel 730counter current to the flow of the coolant 10 through the coolanttransmitter 710. In some embodiments, the coolant 10 can flow throughthe evaporation vessel 730 parallel to the coolant transmitter 710. Insome embodiments, the evaporation vessel 730 can be an annular spacearound the coolant transmitter 710. In other words, the evaporationvessel can envelop or surround the coolant transmitter 710. In someembodiments, the cooling system can be fixed to a power transmissionline, such that the evaporation vessel 730 is in contact with the powertransmission line.

In some embodiments, the coolant transmitter 710 can directly encase atransmission line conductor (not shown). In other words, thetransmission line conductor can run through the coolant transmitter 710.In some embodiments, the cooling system 700 can include asuperconducting cable (not shown) disposed in the coolant transmitter710 and running the length of the coolant transmitter 710. In someembodiments, the cooling system 700 can include a structural tensioncable (not shown) disposed in the coolant transmitter 710 and runningthe length of the coolant transmitter 710. In some embodiments, thetransmission line conductor, the superconducting cable, and/or thestructural tension cable can run through a space surrounded by theevaporation vessel 730.

FIG. 8 illustrates a cooling system 800, according to an embodiment. Asshown, the cooling system 800 includes a coolant transmitter 810 (alsoreferred to as a “header tube”), an exit stream conduit 820, a spraytube 822, an evaporation vessel 830, a throttle 841, an orifice 842, anexit vent 856, and a level sensor 860. In some embodiments, the coolanttransmitter 810, the exit stream conduit 820, the evaporation vessel830, the orifice 842, and the exit vent 856 can be the same orsubstantially similar to the coolant transmitter 710, the exit streamconduit 720, the evaporation vessel 730, the orifice 742, and the exitvent 756, as described above with reference to FIG. 7. In someembodiments, the throttle 841 and the level sensor 860 can be the sameor substantially similar to the throttle 241 and the level sensor 260,as described above with reference to FIG. 2. Thus, certain aspects ofthe coolant transmitter 810, the exit stream conduit 820, theevaporation vessel 830, the throttle 841, the exit vent 856, and thelevel sensor 860 are not described in greater detail herein. As shown,the coolant 10 flows as a liquid along liquid lines L and as a vaporalong vapor lines V.

As shown, a portion of the coolant 10 flowing through the coolanttransmitter 810 is diverted to the exit stream conduit 820. From theexit stream conduit 820, the coolant 10 flows through the throttle 841to enter the spray tube 822. The throttle 841 regulates flow of coolant10 from the coolant transmitter 810 to the spray tube 822. In someembodiments, the throttle 841 can include one or more valves. Thecoolant 10 flows through the spray tube 822 along liquid lines L. Thecoolant 10 flows from the spray tube 822 into the evaporation vessel 830via the orifice 842. The coolant 10 enters the evaporation vessel 830 asa vapor. In some embodiments, the coolant 10 is sprayed into theevaporation vessel 830 where the coolant 10 subsequently boils.Conduction occurs across the walls of the coolant transmitter 810 andthe spray tube 822 to transfer heat from the evaporation vessel 830 tothe coolant transmitter 810 and the spray tube 822. In addition, forcedconvective heat transfer occurs between the coolant 10 in theevaporation vessel 830 and the coolant 10 in the coolant transmitter 810and the spray tube 822. As shown, the coolant 10 flows through theevaporation vessel 830 counter current to the flow of the coolant 10through the coolant transmitter 810 and the spray tube 822. In someembodiments, the coolant 10 can flow through the evaporation vessel 830parallel to the coolant transmitter 810 and the spray tube 822.

If an excess amount of the coolant 10 exits the spray tube 822 to theevaporation vessel 830, some of the coolant 10 can accumulate in theevaporation vessel 830 as a liquid. The level sensor 860 detects thelevel of liquid in the evaporation vessel 830 and can communicate withthe throttle 841. For example, if the level sensor 860 detects more thana desired amount of liquid in the evaporation vessel 830, the throttle841 can adjust its opening such that less of the coolant 10 passes intothe spray tube 822, and consequently less of the coolant 10 passes intothe evaporation vessel 830 via the orifice 842. Conversely, if theamount of heat transfer between the evaporation vessel 830 and thecoolant transmitter 810 and the spray tube 822 is less than desired(e.g., detected via temperature sensors), the throttle 841 can adjustits opening such that more of the coolant 10 passes into the spray tube822. Consequently, more of the coolant 10 would then pass into theevaporation vessel 830.

FIGS. 9A-9B illustrate a cooling system 900 and various componentsthereof, according to an embodiment. As shown, the cooling system 900includes a coolant transmitter 910, evaporation vessels 930A, 930B(collectively referred to as evaporation vessels 930 or “coolingtubes”), a throttle 941, orifices 942A, 942B (collectively referred toas orifices 942), exit vents 956A, 956B, (collectively referred to asexit vents 956), and a level sensor 960. In some embodiments, thecoolant transmitter 910, the evaporation vessels 930, the throttle 941,the orifices 942, the exit vents 956, and the level sensor 960 can bethe same or substantially similar to the coolant transmitter 810, theevaporation vessel 830, the throttle 841, the orifice 842, the exit vent856, and the level sensor 860, as described above with reference to FIG.8. Thus, certain aspects of the coolant transmitter 910, the evaporationvessels 930, the throttle 941, the orifices 942, the exit vents 956, andthe level sensor 960 are not described in greater detail herein. Asshown, the coolant 10 flows as a liquid along liquid lines L and as avapor along vapor lines V.

FIG. 9A illustrates a cooling system 900, while FIG. 9B illustrates theentry of liquid coolant into the evaporation vessel 930A via the orifice942A. As shown in FIG. 9B, the coolant 10 enters the orifice 942A as apressurized liquid, flowing along liquid line L. Upon entry into theevaporation vessel 930A, the coolant 10 expands to become a vapor, asthe evaporation vessel 930A is maintained at a lower pressure than thecoolant transmitter 910. In other words, the coolant is sprayed into theevaporation vessels 930 and boils on contact with a warmer surface or onmixing with warmer vapor, thereby cooling the evaporation vessels 930.

As shown, the evaporation vessels 930 are tubes disposed in the coolanttransmitter 910. As shown, the coolant 10 flows through a portion of theevaporation vessels 930 counter current to the flow of the coolant 10through the coolant transmitter 910, and then perpendicular to the flowof the coolant 10 through a portion of the coolant transmitter 910. Insome embodiments, the coolant 10 can flow through a portion of theevaporation vessels 930 parallel to the flow of the coolant 10 throughthe coolant transmitter 910, and then perpendicular to the flow of thecoolant 10 through a portion of the coolant transmitter 910. As shown,the evaporation vessel 930A is vented to atmospheric pressure or nearatmospheric pressure. As shown, the flow of the coolant 10 through theevaporation vessel 930B is controlled by the throttle 941 and the levelsensor 960. In some embodiments, the cooling system 900 can includemultiple evaporation vessels vented to atmospheric pressure or nearatmospheric pressure (e.g., evaporation vessel 930A). In someembodiments, the cooling system 900 can include 0, 1, 2, 3, 4, 5, 6, 7,8, 9, 10, or more evaporation vessels vented to atmospheric pressure ornear atmospheric pressure. In some embodiments, the cooling system 900can include multiple evaporation vessels, through which coolant flow iscontrolled by a throttle and a level sensor (e.g., evaporation vessel930B). In some embodiments, the cooling system 900 can include 0, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, or more evaporation vessels, through whichcoolant flow is controlled by a throttle and a level sensor.

FIG. 10 illustrates a cooling system 1000, according to an embodiment.As shown, the cooling system 1000 includes a coolant transmitter, anexit stream conduit 1020, an evaporation vessel 1030, an orifice 1042, aheat exchanger 1050, an exit vent 1056, and a TIJ 1070. In someembodiments, the coolant transmitter 1010, the exit stream conduit 1020,the evaporation vessel 1030, the orifice 1042, the heat exchanger 1050,the exit vent 1056, and the TIJ 1070 can be the same or substantiallysimilar to the coolant transmitter 410, the exit stream conduit 420, theevaporation vessel 430, the orifice 442, the heat exchanger 450, theexit vent 456, and the TIJ 470, as described above with reference toFIG. 4. Thus, certain aspects of the coolant transmitter 1010, the exitstream conduit 1020, the evaporation vessel 1030, the orifice 1042, theheat exchanger 1050, and the TIJ 1070 are not described in greaterdetail herein. As shown, the coolant 10 flows as a liquid along liquidlines L and as a vapor along vapor lines V.

In some embodiments, the heat exchanger 1050 can be an integral part ofthe flow line of the coolant 10. In some embodiments, the heat exchanger1050 can include a surface enhanced for forced convective heat transferprotruding into the flow path of the coolant 10. In some embodiments,the enhanced surface in the heat exchanger 1050 can include fins,fingers, or any other surface features to facilitate heat transfer. Insome embodiments, the enhanced surface can include a base that is fixedto, or passes through, a pressure barrier, thus creating a strongthermal link with the coolant 10 in the evaporation vessel 1030.

FIG. 11 is a block diagram of a method 1100 of cooling a subcooledliquid, according to an embodiment. The method 1100 includes flowing anamount of subcooled liquid through a conduit, wherein the subcooledliquid is at a pressure greater than atmospheric pressure at step 1102.The method 1100 further includes diverting a portion of the subcooledliquid into an evaporation vessel, wherein the evaporation vessel is ata lower pressure than the conduit, such that the portion of thesubcooled liquid becomes boiling liquid at step 1104. The method 1100further includes exposing a remaining amount of subcooled liquid in theconduit to a heat transfer interface while exposing the boiling liquidto the heat transfer interface at step 1106 and transferring heat fromthe subcooled liquid to the boiling liquid to reduce the temperature ofthe subcooled liquid at step 1108.

In some embodiments, the subcooled liquid flowed through the conduit atstep 1102 can include a coolant. In some embodiments, the subcooledliquid can include LN, liquid helium, liquid neon, liquid air, liquidhydrogen, liquid natural gas, or any combination thereof. In someembodiments, the subcooled liquid can flow through the conduit at a flowrate of at least about 10 L/min, at least about 20 L/min, at least about30 L/min, at least about 40 L/min, at least about 50 L/min, at leastabout 60 L/min, at least about 70 L/min, at least about 80 L/min, atleast about 90 L/min, at least about 100 L/min, at least about 200L/min, at least about 300 L/min, at least about 400 L/min, at leastabout 500 L/min, at least about 600 L/min, at least about 700 L/min, atleast about 800 L/min, at least about 900 L/min, at least about 1m³/min, at least about 2 m³/min, at least about 3 m³/min, at least about4 m³/min, at least about 5 m³/min, at least about 6 m³/min, at leastabout 7 m³/min, at least about 8 m³/min, or at least about 9 m³/min. Insome embodiments, the subcooled liquid can flow through the conduit at aflow rate of no more than about 10 m³/min, no more than about 9 m³/min,no more than about 8 m³/min, no more than about 7 m³/min, no more thanabout 6 m³/min, no more than about 5 m³/min, no more than about 4m³/min, no more than about 3 m³/min, no more than about 2 m³/min, nomore than about 1 m³/min, no more than about 900 L/min, no more thanabout 800 L/min, no more than about 700 L/min, no more than about 600L/min, no more than about 500 L/min, no more than about 400 L/min, nomore than about 300 L/min, no more than about 200 L/min, no more thanabout 100 L/min, no more than about 90 L/min, no more than about 80L/min, no more than about 70 L/min, no more than about 60 L/min, no morethan about 50 L/min, no more than about 40 L/min, no more than about 30L/min, or no more than about 20 L/min. Combinations of theabove-referenced ranges for the amount of the flow rate of the subcooledliquid through the conduit are also possible (e.g., at least about 20L/min and no more than about 10 m³/min or at least about 100 L/min andno more than about 500 L/min), inclusive of all values and rangestherebetween. In some embodiments, the flow rate of the subcooled liquidthrough the conduit can be about 9 L/min, about 10 L/min, about 20L/min, about 30 L/min, about 40 L/min, about 50 L/min, about 60 L/min,about 70 L/min, about 80 L/min, about 90 L/min, about 100 L/min, about200 L/min, about 300 L/min, about 400 L/min, about 500 L/min, about 600L/min, about 700 L/min, about 800 L/min, about 900 L/min, about 1m³/min, about 2 m³/min, about 3 m³/min, about 4 m³/min, about 5 m³/min,about 6 m³/min, about 7 m³/min, about 8 m³/min, about 9 m³/min, or about10 m³/min.

In some embodiments, the subcooled liquid can be maintained at a gaugepressure of at least about 1 bar, at least about 2 bar, at least about 3bar, at least about 4 bar, at least about 5 bar, at least about 6 bar,at least about 7 bar, at least about 8 bar, at least about 9 bar, atleast about 10 bar, at least about 15 bar, at least about 20 bar, atleast about 25 bar, at least about 30 bar, at least about 35 bar, atleast about 40 bar, or at least about 45 bar. In some embodiments, thesubcooled liquid can be maintained at a gauge pressure of no more thanabout 50 bar, no more than about 45 bar, no more than about 40 bar, nomore than about 35 bar, no more than about 30 bar, no more than about 25bar, no more than about 20 bar, no more than about 15 bar, no more thanabout 10 bar, no more than about 9 bar, no more than about 8 bar, nomore than about 7 bar, no more than about 6 bar, no more than about 5bar, no more than about 4 bar, no more than about 3 bar, or no more thanabout 2 bar. Combinations of the above-referenced gauge pressures of thesubcooled liquid are also possible (e.g., at least about 1 bar and nomore than about 50 bar or at least about 10 bar and no more than about30 bar), inclusive of all values and ranges therebetween. In someembodiments, the subcooled liquid 110 can be maintained at a gaugepressure of about 1 bar, about 2 bar, about 3 bar, about 4 bar, about 5bar, about 6 bar, about 7 bar, about 8 bar, about 9 bar, about 10 bar,about 15 bar, about 20 bar, about 25 bar, about 30 bar, about 35 bar,about 40 bar, about 45 bar, or about 50 bar. In some embodiments, thepressure of the subcooled liquid can be maintained via a pump, a boosterpump, a compressor, a centrifugal pump, or any combination thereof.

In some embodiments, the weight percentage of the subcooled liquiddiverted into the evaporation vessel at step 1104 can be at least about0.5 wt %, at least about 1 wt %, at least about 1.5 wt %, at least about2 wt %, at least about 2.5 wt %, at least about 3 wt %, at least about3.5 wt %, at least about 4 wt %, at least about 4.5 wt %, at least about5 wt %, at least about 5.5 wt %, at least about 6 wt %, at least about6.5 wt %, at least about 7 wt %, at least about 7.5 wt %, at least about8 wt %, at least about 8.5 wt %, at least about 9 wt %, or at leastabout 9.5 wt %. In some embodiments, the weight percentage of thesubcooled liquid diverted into the evaporation vessel at step 1104 canbe no more than about 10 wt %, no more than about 9.5 wt %, no more thanabout 9 wt %, no more than about 8.5 wt %, no more than about 8 wt %, nomore than about 7.5 wt %, no more than about 7 wt %, no more than about6.5 wt %, no more than about 6 wt %, no more than about 5.5 wt %, nomore than about 5 wt %, no more than about 4.5 wt %, no more than about4 wt %, no more than about 3.5 wt %, no more than about 3 wt %, no morethan about 2.5 wt %, no more than about 2 wt %, no more than about 1.5wt %, or no more than about 1 wt %. Combinations of the above-referencedranges for the weight percentage of subcooled liquid diverted to theevaporation vessel at step 1104 are also possible (e.g., at least about0.5 wt % and no more than about 10 wt % or at least about 1 wt % and nomore than about 5 wt %), inclusive of all values and rangestherebetween. In some embodiments, the weight percentage of thesubcooled liquid diverted to the evaporation vessel at step 1104 can beabout 0.5 wt %, about 1 wt %, about 1.5 wt %, about 2 wt %, about 2.5 wt%, about 3 wt %, about 3.5 wt %, about 4 wt %, about 4.5 wt %, about 5wt %, about 5.5 wt %, about 6 wt %, about 6.5 wt %, about 7 wt %, about7.5 wt %, about 8 wt %, about 8.5 wt %, about 9 wt %, about 9.5 wt %, orabout 10 wt %.

In some embodiments, the subcooled liquid can be diverted to theevaporation vessel at step 1104 at a rate of at least about 0.1 L/min,at least about 0.2 L/min, at least about 0.3 L/min, at least about 0.4L/min, at least about 0.5 L/min, at least about 0.6 L/min, at leastabout 0.7 L/min, at least about 0.8 L/min, at least about 0.9 L/min, atleast about 1 L/min, at least about 2 L/min, at least about 3 L/min, atleast about 4 L/min, at least about 5 L/min, at least about 6 L/min, atleast about 7 L/min, at least about 8 L/min, at least about 9 L/min, atleast about 10 L/min, at least about 20 L/min, at least about 30 L/min,at least about 40 L/min, at least about 50 L/min, at least about 60L/min, at least about 70 L/min, at least about 80 L/min, at least about90 L/min, at least about 100 L/min, at least about 200 L/min, at leastabout 300 L/min, at least about 400 L/min, at least about 500 L/min, atleast about 600 L/min, at least about 700 L/min, at least about 800L/min, or at least about 900 L/min. In some embodiments, the subcooledliquid can be diverted to the evaporation vessel at step 1104 at a rateof no more than about 1,000 L/min, no more than about 900 L/min, no morethan about 800 L/min, no more than about 700 L/min, no more than about600 L/min, no more than about 500 L/min, no more than about 400 L/min,no more than about 300 L/min, no more than about 200 L/min, no more thanabout 100 L/min, no more than about 90 L/min, no more than about 80L/min, no more than about 70 L/min, no more than about 60 L/min, no morethan about 50 L/min, no more than about 40 L/min, no more than about 30L/min, no more than about 20 L/min, no more than about 10 L/min, no morethan about 9 L/min, no more than about 8 L/min, no more than about 7L/min, no more than about 6 L/min, no more than about 5 L/min, no morethan about 4 L/min, no more than about 3 L/min, no more than about 2L/min, no more than about 1 L/min, no more than about 0.9 L/min, no morethan about 0.8 L/min, no more than about 0.7 L/min, no more than about0.6 L/min, no more than about 0.5 L/min, no more than about 0.4 L/min,no more than about 0.3 L/min, no more than about 0.2 L/min, or no morethan about 0.1 L/min. Combinations of the above-referenced ranges forthe amount of subcooled liquid diverted to the evaporation vessel atstep 1104 are also possible (e.g., at least about 0.1 L/min and no morethan about 1,000 L/min or at least about 10 L/min and no more than about50 L/min), inclusive of all values and ranges therebetween. In someembodiments, the subcooled liquid can be diverted to the evaporationvessel at step 1104 at a rate of about 0.1 L/min, about 0.2 L/min, about0.3 L/min, about 0.4 L/min, about 0.5 L/min, about 0.6 L/min, about 0.7L/min, about 0.8 L/min, about 0.9 L/min, about 1 L/min, about 2 L/min,about 3 L/min, about 4 L/min, about 5 L/min, about 6 L/min, about 7L/min, about 8 L/min, about 9 L/min, about 10 L/min, about 20 L/min,about 30 L/min, about 40 L/min, about 50 L/min, about 60 L/min, about 70L/min, about 80 L/min, about 90 L/min, about 100 L/min, about 200 L/min,about 300 L/min, about 400 L/min, about 500 L/min, about 600 L/min,about 700 L/min, about 800 L/min, about 900 L/min, or about 1,000 L/min.

The subcooled liquid becomes boiling liquid in the evaporation vessel.In some embodiments, the evaporation vessel can be vented to atmosphericpressure or near atmospheric pressure. In some embodiments, vapor exitsthe evaporation vessel at or near atmospheric pressure and can becaptured (e.g., for later use) and/or transported (e.g., to a furtherheat exchanger that warms the vapor to an ambient temperature prior toventing).

In some embodiments, step 1106 can include passing the remainingsubcooled liquid through a first side of a heat exchanger while passingthe boiling liquid through a second side of the heat exchanger, thesecond side opposite the first side. In some embodiments, forcedconvective heat transfer can occur at step 1108. In some embodiments,conductive heat transfer can occur at step 1108. In some embodiments,forced convective heat transfer can occur via flow of the subcooledliquid and the boiling liquid. In some embodiments, conductive heattransfer can occur via walls of the heat exchanger or heat exchangeinterface.

In some embodiments, the heat transfer from the boiling liquid to thesubcooled liquid at step 1108 can reduce the temperature of thesubcooled liquid by at least about 0.1 K, at least about 0.2 K, at leastabout 0.3 K, at least about 0.4 K, at least about 0.5 K, at least about0.6 K, at least about 0.7 K, at least about 0.8 K, at least about 0.9 K,at least about 1 K, at least about 2 K, at least about 3 K, at leastabout 4 K, at least about 5 K, at least about 6 K, at least about 7 K,at least about 8 K, or at least about 9 K. In some embodiments, the heattransfer from the boiling liquid to the subcooled liquid at step 1108can reduce the temperature of the subcooled liquid by no more than about10 K, no more than about 9 K, no more than about 8 K, no more than about7 K, no more than about 6 K, no more than about 5 K, no more than about4 K, no more than about 3 K, no more than about 2 K, no more than about1 K, no more than about 0.9 K, no more than about 0.8 K, no more thanabout 0.7 K, no more than about 0.6 K, no more than about 0.5 K, no morethan about 0.4 K, no more than about 0.3 K, or no more than about 0.2 K.Combinations of the above-referenced reductions in temperature of thesubcooled liquid are also possible (e.g., at least about 0.1 K and nomore than about 10 K or at least about 1 K and no more than about 5 K),inclusive of all values and ranges therebetween. In some embodiments,the heat transfer from the boiling liquid to the subcooled liquid atstep 1108 can reduce the temperature of the subcooled liquid by about0.1 K, about 0.2 K, about 0.3 K, about 0.4 K, about 0.5 K, about 0.6 K,about 0.7 K, about 0.8 K, about 0.9 K, about 1 K, about 2 K, about 3 K,about 4 K, about 5 K, about 6 K, about 7 K, about 8 K, or about 9 K.

In some embodiments, a cooling system includes a coolant transmitterthat transmits a coolant at a pressure greater than atmosphericpressure. The cooling system further includes an evaporation vessel thatcontains an amount of the coolant at a boiling point of the coolant anda pressure regulator or pressure reducer at an interface. The interfaceis fluidically coupled to the coolant transmitter and the evaporationvessel. The coolant contained in the evaporation vessel absorbs heatfrom the coolant in the coolant transmitter.

In some embodiments, the cooling system can further include an exitstream conduit fluidically coupled to the coolant transmitter and thepressure regulator or pressure reducer. The exit stream conduit candivert a portion of the coolant from the coolant transmitter to theevaporation vessel.

In some embodiments, a level sensor can be disposed in the evaporationvessel. In some embodiments, the level sensor can be a ball float levelsensor physically coupled to the pressure regulator or pressure reducer.

In some embodiments, the pressure regulator can include a throttleand/or an orifice.

In some embodiments, the cooling system can include a heat exchanger.The heat exchanger can be fluidically coupled to the coolant transmitterand in physical contact with the evaporation vessel, the heat exchangerconfigured to circulate coolant from the coolant transmitter and back tothe coolant transmitter such that heat can transfer from the coolant inthe heat exchanger to the boiling coolant in the evaporation vessel.

In some embodiments, the coolant can include liquid nitrogen, liquidhydrogen, liquid natural gas, another cryogen (e.g., cryogenic fluid) orcoolant, or any combination thereof.

In some embodiments, the evaporation vessel is a heat exchanger at leastpartially disposed in the coolant transmitter.

In some embodiments, the coolant transmitter can include a first portionand a second portion, with the first portion and the second portionfluidically coupled via a heat exchanger. In some embodiments, the heatexchanger can be at least partially submersed in boiling coolant. Insome embodiments, the heat exchanger can include a spiral tube heatexchanger.

In some embodiments, a cooling system includes a coolant transmitterthat transmits a subcooled liquid at a pressure greater than atmosphericpressure, the subcooled liquid exposed to a first side of a heatexchange interface. The cooling system further includes an exit streamconduit that diverts a portion of the subcooled liquid from the coolanttransmitter to an evaporation vessel. The cooling system also includes apressure regulator at a fluidic interface between the exit streamconduit and the evaporation vessel. The pressure regulator maintains apressure difference between the exit stream conduit and the evaporationvessel. The evaporation vessel is configured to contain an amount ofboiling liquid at a pressure lower than the coolant transmitter, theboiling liquid exposed to a second side of the heat exchange interfaceand configured to absorb heat from the subcooled liquid.

In some embodiments, the subcooled liquid and the boiling liquid includea coolant. In some embodiments, the coolant can include liquid nitrogen,liquid hydrogen, liquid natural gas, another cryogen (e.g., cryogenicfluid) or coolant, or any combination thereof.

In some embodiments, the pressure regulator can include a throttle. Insome embodiments, the pressure regulator can include an orifice.

In some embodiments, the first side of the heat exchange interface canbe a shell side of a shell and tube heat exchanger and the second sideof the heat exchange interface can be a tube side of the shell and tubeheat exchanger.

In some embodiments, the coolant transmitter can include a first portionand a second portion fluidically coupled by a spiral tube heatexchanger.

In some embodiments, a method of cooling a subcooled liquid can includeflowing an amount of the subcooled liquid through a conduit, thesubcooled liquid at a pressure greater than atmospheric pressure. Themethod further includes diverting a portion of the subcooled liquid intoan evaporation vessel, the evaporation vessel at a lower pressure thanthe conduit, such that the portion of the subcooled liquid becomesboiling liquid. The method also includes exposing a remaining amount ofsubcooled liquid in the conduit to a heat transfer interface whileexposing the boiling liquid to the heat transfer interface andtransferring heat from the subcooled liquid to the boiling liquid toreduce the temperature of the subcooled liquid.

In some embodiments, the subcooled liquid and the boiling liquid caninclude a coolant. In some embodiments, the coolant can include liquidnitrogen, liquid hydrogen, liquid natural gas, another cryogen (e.g.,cryogenic fluid) or coolant, or any combination thereof.

In some embodiments, cooling systems described herein can be configuredfor the flow of subcooled cryogen coolant in superconducting powerlines. In some embodiments, a portion of the subcooled cryogen can beextracted and allowed to vaporize under atmospheric pressure. In someembodiments, the latent heat of vaporization of the portion of thesubcooled cryogen can cool the remaining subcooled cryogen to a lowertemperature above the boiling temperature of the remaining subcooledcryogen.

In some embodiments, the subcooled cryogen coolant can be removed fromthe transmission line and passed to a heat exchanger. In someembodiments, the heat exchanger can be immersed in a bath of the portionof the subcooled cryogen coolant extracted and allowed to vaporize underatmospheric pressure.

In some embodiments, a level of the portion of the subcooled cryogencoolant can be controlled by means of a level sensor and a valve. Insome embodiments, the portion of the subcooled cryogen coolant can flowthrough a defined flow impedance to maintain the bath at a desired levelor temperature.

In some embodiments, the heat exchanger can be immersed in the flowingsubcooled cryogen coolant and the heat exchanger can be cooled byadmission of the subcooled cryogen coolant. In some embodiments, theadmitted cryogen coolant can boil under atmospheric pressure within theheat exchanger and cool the flowing subcooled cryogen coolant around theheat exchanger.

In some embodiments, the volume of admitted cryogen coolant to the heatexchanger can be controlled by means of a level sensor and a valve.

In some embodiments, the admitted cryogen coolant can flow through adefined flow impedance to maintain the heat exchanger cryogen liquidcoolant at a desired level or temperature.

In some embodiments, a subcooled flowing cryogen coolant can passthrough a heat exchanger cooled by a spray of extracted cryogen coolantboiling at or near atmospheric pressure.

In some embodiments, the extracted cryogen coolant can flow through adefined flow impedance to maintain the bath at a desired cryogen liquidcoolant level or temperature.

In some embodiments, cooling systems described herein can be configuredto extract a portion of a subcooled cryogen coolant and allow theportion of the subcooled cryogen coolant to vaporize under a controlledpressure. In some embodiments, latent heat of vaporization of theportion of the cryogen coolant can be used to cool the remaining cryogencoolant to a temperature above the boiling temperature of the cryogen atthe controlled pressure. In some embodiments, the controlled pressurecan be below, equal to, or above the local atmospheric pressure. In someembodiments, the vaporized cryogen coolant can be allowed to vent to theatmosphere.

In some embodiments, cooling systems described herein can be configuredto extract a portion of a subcooled cryogen coolant and allow theportion of the subcooled cryogen coolant to vaporize under a controlledpressure. In some embodiments, a latent heat of vaporization can be usedto cool the remaining cryogen coolant to a temperature above the boilingtemperature of the cryogen at the controlled pressure. In someembodiments, the controlled pressure can be below, equal to, or abovethe local atmospheric pressure. In some embodiments, the vaporizedcryogen can be captured for further use.

All combinations of the foregoing concepts and additional conceptsdiscussed herewithin (provided such concepts are not mutuallyinconsistent) are contemplated as being part of the subject matterdisclosed herein. The terminology explicitly employed herein that alsomay appear in any disclosure incorporated by reference should beaccorded a meaning most consistent with the particular conceptsdisclosed herein.

The drawings are primarily for illustrative purposes, and are notintended to limit the scope of the subject matter described herein. Thedrawings are not necessarily to scale; in some instances, variousaspects of the subject matter disclosed herein may be shown exaggeratedor enlarged in the drawings to facilitate an understanding of differentfeatures. In the drawings, like reference characters generally refer tolike features (e.g., functionally similar and/or structurally similarelements).

The entirety of this application (including the Cover Page, Title,Headings, Background, Summary, Brief Description of the Drawings,Detailed Description, Embodiments, Abstract, Figures, Appendices, andotherwise) shows, by way of illustration, various embodiments in whichthe embodiments may be practiced. The advantages and features of theapplication are of a representative sample of embodiments only, and arenot exhaustive and/or exclusive. Rather, they are presented to assist inunderstanding and teach the embodiments, and are not representative ofall embodiments. As such, certain aspects of the disclosure have notbeen discussed herein. That alternate embodiments may not have beenpresented for a specific portion of the innovations or that furtherundescribed alternate embodiments may be available for a portion is notto be considered to exclude such alternate embodiments from the scope ofthe disclosure. It will be appreciated that many of those undescribedembodiments incorporate the same principles of the innovations andothers are equivalent. Thus, it is to be understood that otherembodiments may be utilized and functional, logical, operational,organizational, structural and/or topological modifications may be madewithout departing from the scope and/or spirit of the disclosure. Assuch, all examples and/or embodiments are deemed to be non-limitingthroughout this disclosure.

Also, no inference should be drawn regarding those embodiments discussedherein relative to those not discussed herein other than it is as suchfor purposes of reducing space and repetition. For instance, it is to beunderstood that the logical and/or topological structure of anycombination of any program components (a component collection), othercomponents and/or any present feature sets as described in the figuresand/or throughout are not limited to a fixed operating order and/orarrangement, but rather, any disclosed order is exemplary and allequivalents, regardless of order, are contemplated by the disclosure.

The term “determining” encompasses a wide variety of actions and,therefore, “determining” can include calculating, computing, processing,deriving, investigating, looking up (e.g., looking up in a table, adatabase or another data structure), ascertaining and the like. Also,“determining” can include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” can include resolving, selecting, choosing, establishingand the like.

The phrase “based on” does not mean “based only on,” unless expresslyspecified otherwise. In other words, the phrase “based on” describesboth “based only on” and “based at least on.”

Various concepts may be embodied as one or more methods, of which atleast one example has been provided. The acts performed as part of themethod may be ordered in any suitable way. Accordingly, embodiments maybe constructed in which acts are performed in an order different thanillustrated, which may include performing some acts simultaneously, eventhough shown as sequential acts in illustrative embodiments. As such,some of these features may be mutually contradictory, in that theycannot be simultaneously present in a single embodiment. Similarly, somefeatures are applicable to one aspect of the innovations, andinapplicable to others.

In addition, the disclosure may include other innovations not presentlydescribed. Applicant reserves all rights in such innovations, includingthe right to embodiment such innovations, file additional applications,continuations, continuations-in-part, divisionals, and/or the likethereof. As such, it should be understood that advantages, embodiments,examples, functional, features, logical, operational, organizational,structural, topological, and/or other aspects of the disclosure are notto be considered limitations on the disclosure as defined by theembodiments or limitations on equivalents to the embodiments. Dependingon the particular desires and/or characteristics of an individual and/orenterprise user, database configuration and/or relational model, datatype, data transmission and/or network framework, syntax structure,and/or the like, various embodiments of the technology disclosed hereinmay be implemented in a manner that enables a great deal of flexibilityand customization as described herein.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

As used herein, in particular embodiments, the terms “about” or“approximately” when preceding a numerical value indicates the valueplus or minus a range of 10%. Where a range of values is provided, it isunderstood that each intervening value, to the tenth of the unit of thelower limit unless the context clearly dictates otherwise, between theupper and lower limit of that range and any other stated or interveningvalue in that stated range is encompassed within the disclosure. Thatthe upper and lower limits of these smaller ranges can independently beincluded in the smaller ranges is also encompassed within thedisclosure, subject to any specifically excluded limit in the statedrange. Where the stated range includes one or both of the limits, rangesexcluding either or both of those included limits are also included inthe disclosure.

The indefinite articles “a” and “an,” as used herein in thespecification and in the embodiments, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theembodiments, should be understood to mean “either or both” of theelements so conjoined, i.e., elements that are conjunctively present insome cases and disjunctively present in other cases. Multiple elementslisted with “and/or” should be construed in the same fashion, i.e., “oneor more” of the elements so conjoined. Other elements may optionally bepresent other than the elements specifically identified by the “and/or”clause, whether related or unrelated to those elements specificallyidentified. Thus, as a non-limiting example, a reference to “A and/orB”, when used in conjunction with open-ended language such as“comprising” can refer, in one embodiment, to A only (optionallyincluding elements other than B); in another embodiment, to B only(optionally including elements other than A); in yet another embodiment,to both A and B (optionally including other elements); etc.

As used herein in the specification and in the embodiments, “or” shouldbe understood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the embodiments, “consisting of,” will refer to the inclusion ofexactly one element of a number or list of elements. In general, theterm “or” as used herein shall only be interpreted as indicatingexclusive alternatives (i.e. “one or the other but not both”) whenpreceded by terms of exclusivity, such as “either,” “one of” “only oneof,” or “exactly one of” “Consisting essentially of,” when used in theembodiments, shall have its ordinary meaning as used in the field ofpatent law.

As used herein in the specification and in the embodiments, the phrase“at least one,” in reference to a list of one or more elements, shouldbe understood to mean at least one element selected from any one or moreof the elements in the list of elements, but not necessarily includingat least one of each and every element specifically listed within thelist of elements and not excluding any combinations of elements in thelist of elements. This definition also allows that elements mayoptionally be present other than the elements specifically identifiedwithin the list of elements to which the phrase “at least one” refers,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, “at least one of A and B” (or,equivalently, “at least one of A or B,” or, equivalently “at least oneof A and/or B”) can refer, in one embodiment, to at least one,optionally including more than one, A, with no B present (and optionallyincluding elements other than B); in another embodiment, to at leastone, optionally including more than one, B, with no A present (andoptionally including elements other than A); in yet another embodiment,to at least one, optionally including more than one, A, and at leastone, optionally including more than one, B (and optionally includingother elements); etc.

In the embodiments, as well as in the specification above, alltransitional phrases such as “comprising,” “including,” “carrying,”“having,” “containing,” “involving,” “holding,” “composed of,” and thelike are to be understood to be open-ended, i.e., to mean including butnot limited to. Only the transitional phrases “consisting of” and“consisting essentially of” shall be closed or semi-closed transitionalphrases, respectively, as set forth in the United States Patent OfficeManual of Patent Examining Procedures, Section 2111.03.

1. A cooling system, comprising: a coolant transmitter configured totransmit a coolant at a pressure greater than atmospheric pressure; anevaporation vessel at atmospheric pressure, the evaporation vesselincluding a level sensor and configured to contain an amount of thecoolant at a boiling point of the coolant; and a pressure reducerfluidically coupled to the coolant transmitter and the evaporationvessel, wherein the cooling system is configured such that heat istransferred from the coolant in the coolant transmitter to the coolantcontained in the evaporation vessel.
 2. The cooling system of claim 1,further comprising an exit stream conduit fluidically coupled to thecoolant transmitter and the pressure reducer, the exit stream conduitconfigured to divert a portion of the coolant from the coolanttransmitter to the evaporation vessel.
 3. (canceled)
 4. The coolingsystem of claim 1, wherein the level sensor is a ball float level sensorphysically coupled to the pressure reducer.
 5. The cooling system ofclaim 1, wherein the pressure reducer includes a throttle.
 6. Thecooling system of claim 1, wherein the pressure reducer includes anorifice.
 7. The cooling system of claim 1, further comprising a heatexchanger, the heat exchanger fluidically coupled to the coolanttransmitter and in physical contact with the evaporation vessel, theheat exchanger configured to circulate coolant from the coolanttransmitter and back to the coolant transmitter such that heat cantransfer from the coolant in the heat exchanger to the boiling coolantin the evaporation vessel.
 8. The cooling system of claim 1, wherein thecoolant includes one of liquid nitrogen, liquid hydrogen, liquid naturalgas, or a combination thereof.
 9. The cooling system of claim 1, whereinthe evaporation vessel is a heat exchanger at least partially disposedin the coolant transmitter.
 10. The cooling system of claim 1, whereinthe coolant transmitter includes a first portion and a second portion,the first portion and the second portion fluidically coupled via a heatexchanger.
 11. The cooling system of claim 9, wherein the heat exchangeris at least partially submersed in boiling coolant.
 12. The coolingsystem of claim 9, wherein the heat exchanger includes a spiral tubeheat exchanger.
 13. The cooling system of claim 1, further comprising athermally insulated jacket disposed around the outside of theevaporation vessel.
 14. The cooling system of claim 1, furthercomprising: a power transmission line in contact with the coolanttransmitter. 15-24. (canceled)
 25. A cooling system, comprising: acoolant transmitter configured to transmit a coolant at a pressuregreater than atmospheric pressure; an evaporation vessel at atmosphericpressure at least partially disposed in the coolant transmitter, theevaporation vessel including a heat exchanger and configured to containan amount of the coolant at a boiling point of the coolant; and apressure reducer fluidically coupled to the coolant transmitter and theevaporation vessel, wherein the cooling system is configured such thatheat is transferred from the coolant in the coolant transmitter to thecoolant contained in the evaporation vessel.
 26. The cooling system ofclaim 25, further comprising an exit stream conduit fluidically coupledto the coolant transmitter and the pressure reducer, the exit streamconduit configured to divert a portion of the coolant from the coolanttransmitter to the evaporation vessel.
 27. The cooling system of claim25, wherein the level sensor is a ball float level sensor physicallycoupled to the pressure reducer.
 28. The cooling system of claim 25,wherein the pressure reducer includes a throttle.
 29. The cooling systemof claim 25, wherein the pressure reducer includes an orifice.
 30. Thecooling system of claim 25, wherein the heat exchanger is fluidicallycoupled to the coolant transmitter and in physical contact with theevaporation vessel, the heat exchanger configured to circulate coolantfrom the coolant transmitter and back to the coolant transmitter suchthat heat can transfer from the coolant in the heat exchanger to theboiling coolant in the evaporation vessel.
 31. The cooling system ofclaim 25, wherein the coolant includes one of liquid nitrogen, liquidhydrogen, liquid natural gas, or a combination thereof.
 32. The coolingsystem of claim 25, wherein the coolant transmitter includes a firstportion and a second portion, the first portion and the second portionfluidically coupled via the heat exchanger.
 33. The cooling system ofclaim 25, wherein the heat exchanger is at least partially submersed inboiling coolant.
 34. The cooling system of claim 25, wherein the heatexchanger includes a spiral tube heat exchanger.
 35. The cooling systemof claim 25, further comprising a thermally insulated jacket disposedaround the outside of the evaporation vessel.
 36. The cooling system ofclaim 25, further comprising: a power transmission line in contact withthe coolant transmitter.
 37. A cooling system, comprising: a coolanttransmitter configured to transmit a coolant at a pressure greater thanatmospheric pressure; an evaporation vessel at atmospheric pressure, theevaporation vessel configured to contain an amount of the coolant at aboiling point of the coolant; a thermally insulated jacket disposedaround the outside of the evaporation vessel; and a pressure reducerfluidically coupled to the coolant transmitter and the evaporationvessel, wherein the cooling system is configured such that heat istransferred from the coolant in the coolant transmitter to the coolantcontained in the evaporation vessel.
 38. The cooling system of claim 37,further comprising an exit stream conduit fluidically coupled to thecoolant transmitter and the pressure reducer, the exit stream conduitconfigured to divert a portion of the coolant from the coolanttransmitter to the evaporation vessel.
 39. The cooling system of claim37, wherein the level sensor is a ball float level sensor physicallycoupled to the pressure reducer.
 40. The cooling system of claim 37,wherein the pressure reducer includes a throttle.
 41. The cooling systemof claim 37, wherein the pressure reducer includes an orifice.
 42. Thecooling system of claim 37, further comprising a heat exchanger, theheat exchanger fluidically coupled to the coolant transmitter and inphysical contact with the evaporation vessel, the heat exchangerconfigured to circulate coolant from the coolant transmitter and back tothe coolant transmitter such that heat can transfer from the coolant inthe heat exchanger to the boiling coolant in the evaporation vessel. 43.The cooling system of claim 37, wherein the coolant includes one ofliquid nitrogen, liquid hydrogen, liquid natural gas, or a combinationthereof.
 44. The cooling system of claim 37, wherein the coolanttransmitter includes a first portion and a second portion, the firstportion and the second portion fluidically coupled via a heat exchanger.45. The cooling system of claim 37, wherein the evaporation vessel is aheat exchanger at least partially disposed in the coolant transmitterand the heat exchanger is at least partially submersed in boilingcoolant.
 46. The cooling system of claim 37, wherein the evaporationvessel is a heat exchanger at least partially disposed in the coolanttransmitter and the heat exchanger includes a spiral tube heatexchanger.
 47. The cooling system of claim 37, further comprising: apower transmission line in contact with the coolant transmitter.